<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<form method="post" name="test">
    <input type="radio" name="color" />红色<br />
    <input type="radio" name="color" />绿色<br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br />
    <input type="submit" name="send" value="提交"/>
</form>

<script type="text/javascript">
   var fm = document.test;
   var sub = fm.send;
   var radio = fm.color;
   sub.onclick = function() {
       radio.focus();
   }
</script>



</body>
</html>